At Olive Garden, pasta is served soft, not al dente or slightly firm, the traditional Italian method. Meat is often served on top of pasta, and cheese is mixed with seafood, two preparations rare in authentic Italian cuisine. The reason: Adding a protein to a dish makes it seem like a better value. Also, Americans have a strong preference for meat and cheese.

Chefs at Olive Garden headquarters reverse-engineer menu items from real Italian dishes. A current seasonal dish, baked pasta romana—a mix of lasagna pasta, rich cheese sauce, spinach and either a beef or chicken topping—started as a fresh-torn pasta dish with olive oil, garlic and herbs eaten by company chefs on a trip to Northern Italy.

Chefs found the dish "really rustic, but still kind of normal," the magic formula Olive Garden chefs often look for, says Marie Grimm, director of culinary development for Olive Garden. In restaurant tests, the company tried a chicken version with roasted tomato sauce, but diners didn't find it "cravable," says Ms. Grimm. The restaurant switched to a cheese sauce.